Hydraulic power unit including bed plate construction



HYDRAULIC POWER UNIT INCLUDING BED PLATE CONSTRUCTION June 22, 1965 N. F. MacMlLLlN 2 Sheets-Sheet 1 Filed Oct. 16, 1963 rINVENTOR.

. MACMILLIN AM /M ATTYS.

June 22, 1965 MacMlLLIN 3,190,507

HYDRAULIC POWER UNIT INCLUDING BED PLATE CONSTRUCTION Filed Oct. 16, 1963 2 Sheets-Sheet 2 NVENTOR.

NORMAN MACMILLIN BY W .;MLAJ, Wm

Ari-V51 United States Patent 3,19%,997 HYR'IQRAULNI PQWER EJNH iNiClLlUDllNG PLATE C ZERSTRUCTHQN Norman Mach .Eillin, Highland Park, lill., assignor to Maeltiiilin Hydraulic Engineering Corporation, Sirohie,

iii, a corporation of lllinois lFided 0st. 16, 1963, Ser. No. 316,743 Claims. (Cl. 222-4553) The present invention relates to hydraulic power units and more particularly to a self contained motor and pump combination for supplying hydraulic fluid under pressure.

It is an object of the present invention to provide an hydraulic pov er unit which includes a novel bed plate construction suitable for mounting the motor pump and auxiliary devices and which is superimposed on a rectangular enclosure forming an oil reservoir or sump and which is capable of being used universally wherever a source of pressurized fluid is required.

It is one of the main objects of the present invention to provide a bed plate for a power unit which performs a number of different functions formerly performed by a built-up assembly of a number of pieces but which is, on the contrary, of simple unitary cast construction. It is a related object to provide a bed plate for an hydraulic power unit which is inherently strong and rigid and in which mounting surfaces are all formed on the same integral casting insuring accurate alinement between the motor and connected pump simply by securing the latter members in position and without exercising any care or attention on the part of the assembler. It is another object related to the foregoing to provide a bed plate or hydraulic power unit which insures that the motor pump will have the same mounting accuracy and the same eiiective tolerance from unit to unit without the risk of cumulative error which is inherent where a bed plate is formed of a plurality of supporting elements secured one on top of another.

It is still another object of the present invention to provide an hydraulic power unit and bed plate construc tion therefor which permits use of standard NEMA motors of the base-mounted type in common off-theshelf supply and which does not require any special or flange type mounting thereby to minimize the down time in the event that the motor is burned out or requires servicing. it is an object of the invention in one of its aspects to provide a bed plate construction for a power unit which permits custom assembly of a motor having desired voltage, power and speed characteristics with a pump having desired pressure and flow specifications permitting a power unit to be tailored to a particular application simply by bolting the selected motor and pump in place and by securing the bed plate upon a reservoir having a desired fluid capacity, the assembly operation requiring a minimum of shop facilities and being capable of being carried out at the warehouse or other point of shipment at the time the order is filled.

It is an object of the invention in one of its aspects to provide a bed plate for a power unit in which both pump and motor are bolted to readily available surfaces but which nevertheless is effective to protect the user against accidental contact with exposed rotating parts, specifically the shafts and the coupling which serves to couple them together. More specifically, it is an object to provide a bed plate having an integral tower of rectangular shape which serves to mount the pump and auxiliary equipment and which serves to shield the drive coupling with the tower having provision for complete enclosure of the coupling by aflixation of a nameplate which carries identifying information peculiar to the motor-pump combination.

Bdddiid? Patented June 22, 1965 Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawing in which:

FIGURE 1 is a side View of an hydraulic power unit constructed in accordance with the present invention.

FIG. 2 is an end view of the power unit of FIG. 1.

FIG. 3 is a perspective of the novel bed plate construction used in the power unit of the preceding figures.

FIG. 4 is a longitudinal section taken along the line 4-4 in FIG. 2.

FIG. 5 is a transverse section taken through the tower of the bed plate along the line 55 in FIG. 4.

FIG. 6 shows the tower profile as viewed along the line 6(. in FIG. 4.

FIG. 7 is a fragmentary section showing the motor mounting pad and stiileners taken along the line 7-7 in FIG. 4.

While the invention has been described in connection with a preferred embodiment, it will be understood that I do not intend to limit the invention to the particular embodiment shown but intend to cover the various alternative and equivalent constructions included within the spirit and scope of the appended claims.

Turning now to the drawing, a completely assembled power unit constructed in accordance with the present invention, indicated at it), includes a bed plate 11 and motor 12 driving hydraulic pump 13 via a shaft coupling '14. The bed plate lll is supported upon a reser voir 15 of rectangular shape containing a body of hydraulic fluid. The inlet of the pump is connected to a drop or inlet tube 16 while the outlet 17 may be connected to the load by any desired means. The fluid returning from the load is returned to the sump through a sump tube 13.

In accordance with the present invention the bed plate 11 which is preferably of rectangular outline, has formed integrally therewith an upstanding tower of hollow box shape having a first end wall for mounting the hydraulic pump and motor mounting pads adjacent the second end wall for mounting the motor so that its shaft is automatically alined with the shaft of the pump and with a coupling in the tower for coupling the two shafts together. Thus I provide a tower 20 which is cast integrally with the remainder of the bed plate having a first end Wall 21, a second end wall 22, and fiat side walls 23, 24-, the walls preferably defining an upper edge 25 which lies in the horizontal plane. Adjacent the second end wall 22 and cast integrally with the bed plate are first and second motor mounting pads 27, 28. The first end wall 21 of the tower is machined flat and the motor mounting pads 2'7, 28 are machined in a plane which is precisely perpendicular to the mounting surface 21. Moreover, a pump mounting hole 36 is formed in the mounting surface Zll of a diameter which is suited for the mounting of a standard flange type pump with the axis of the pump opening being spaced above the plane of the motor mounting pads by a predetermined distance corresponding to the base-to-axis distance of a standard base-mounted NEMA motor. Tapped openings 31 are provided in the end wall 21 at a spacing suitable for the accommodation of the pump and tapped openings 32 are formed in the motor mounting pads at a lateral spacing which is suited to accommodate a standard drive motor.

In order to facilitate installation of the motor, the adjacent end wall 22 of the tower is preferably relieved by a deep V notch 35 as shown in profile in FIG. 6.

For the purpose of stiffening the tower while preserving the fluid-tight integrity of the mounting plate, the tower is preferably formed with an internal floor 36 which interconnects the ends and the side walls of the tower but which is spaced above the level of the mounting plate. Preferably the floor as is positioned upwardly,

3 toward the center of the tower as far as possible but below the level of the tapped mounting holes 31 and below the level of the V notch 35. Locating the floor 36 slightly below the level of the V notch serves to provide a shallow receptacle to catch the drippings of any oil which may work its way along the motor shaft or the pump shaft.

It is one of the features of the present invention that the upper edges of the side and end walls lie in a plane mounting surface 25 thereby permitting enclosure of the tower by means of a thin rectangular closure plate 37 which conforms to the top of the tower and which is held in place by machine screws at the corners engaging threaded holes 38. Preferably the plate 37, in addition to its enclosing and shielding function, serves as a nameplate for the purpose of identifying the characteristics of a motor and pump employed in the particular combination. The fact that the nameplate 37 must be applied after the assembly of a coupling, i.e., after the characteristics of the motor and pump have been selected tends to insure that the information on the nameplate will be more accurate and up to date than would be the case if the nameplate were permanently installed elsewhere on the bed plate.

It is found that the tower and associated mounting pads, cast integrally with the bed plate, act to rigidity the structure and thus prevent any warping or twisting of the plate or any tendency for the pump mounting surface 21 to depart from its condition of precise perpendicularity with respect to the motor mounting pads 27, 28. This permits a casting of lighter and thinner average cross section to be used than would otherwise be possible. To still further increase the rigidity, 21 depending skirt 40 is integrally formed on the underside of the bed plate spaced inwardly from the periphery by a substantially constant distance. Such skirt serves a number of different purposes. In addition to its rigidifying effect, the skirt is dimensioned to be registeringly received in a standard sized rectangular opening formed in the top of the reservoir 15. The skirt serves, moreover, as a supporting surface thereby protecting adjacent packing or sealing material 41 which is semi-recessed in a groove 42 integrally formed along the base of the skirt. For still further rigidification, the motor mounting pads 27, 28 have cooperating ribs 27a, 28a formed on the underside of the plate. This provides sufiicient section so that the holes 32 which receive the motor mounting bolts may be deep-tapped yet blind to preserve the fluid-tight integrity of the bed plate.

It is one of the features of the construction that the bed plate provides vertical surfaces 23, 24 on the side walls of the tower and on the bed plate itself for the mounting of valves, solenoids, switches, and other auxiliary control elements. In order to enable close nesting of the auxiliary element with respect to the adjacent surfaces 23, 43 and 24, 44 respectively, in spite of the presence of a fillet at the base of the tower, the tower may have a peripheral groove 45 extending about its base as shown.

To keep the bed plate assembled on the reservoir, any desired attaching means may be used. I prefer to employ toggle type hold-down catches 47, 43 secured to the end walls of the reservoir and catching the ends of the bed plate. In the case of hydraulic power units of the present design in smaller sizes, and where maximum portability is desired, the plate 37 may be made somewhat thicker than shown and may be provided with a handle located as nearly as possible along the center of gravity.

It is found that using a bed plate formed of an integral casting or molding and made of metal such as cast aluminum, the construction is not only rigid in the sense of resisting dimensional change but is inherently sound deadening. It would appear that because of the integral tower and mounting pads the drumhead effect which characterizes welded bed plates is substantially overcome.

In addition to the operating advantages of the present construction, already discussed, it is found that the integral bed plate construction enables substantial stocking and operating economies. Thus the cost of producing an integral casting, in quantity production, and assuming use of about the same poundage of material, is less than where the bed plate and supporting surfaces is built up from separate pieces of metal welded or otherwise secured together. Moreover, a high degree of accuracy may be achieved at low cost simply by machining the two mounting surfaces 21 and 27, 28 respectively while the plate is maintained in a positioning jig. This omits the possibility of a cumulative positioning error which might occur where individual parts, each having its own tolerance, are stacked one on another to form a total assembly. The selection of the base to axis dimension, i.e., the spacing between the motor mounting pads 27, 28 and the axis of the hole 31) is a matter well within the skill of the art, this spacing being made to correspond to the standard NEMA spacing employed for motors having a range of voltage and power ratings. Moreover, the pump mounting hole 3b and the spacing of the tapped holes 31 for the pump mounting bolts may be standard industry dimensions for hydraulic pumps having a relatively wide range of pressure, speed and delivery. While the pump and motor are separately mounted, the mounts therefor may be approximately coordinated on a horsepower basis for a bed plate of given size. Thus, using a limited number of bed plates, in a few graduated sizes, it is possible to accommodate an almost infinite range of motor and pump characteristics. Thus the bed plates may be stocked as a warehouse item and motors and pumps may be afiixed thereto in only a few minutes time at the point of warehousing or shipment in order to meet any specific customer requirement. The total inventory may therefore be reduced to a small fraction of that which would be required if completely assembled units were kept in stock.

Moreover, since the present power unit employs a conventional base mounted motor in easy supply, which is to be contrasted with special flange-type motors, it is a small matter to replace the motor even from limited stock where service becomes necessary.

I claim as my invention:

1. In an hydraulic power unit the combination comprising a horizontal bed plate of unitary cast construction and having a generally rectangular outline, an upstanding tower of hollow box shape cast integral with the bed plate and having first and second end walls together with side walls defining an upper edge lying in a substantially horizontal plane, motor mounting pads integrally cast with the bed plate adjacent the second end wall, said first end wall having a flat surface formed thereon and a hole bored therein for flange mounting of an hydraulic pump, said motor pads being perpendicular to said fiat surface and in a plane which is spaced at a predetermined distance with respect to the hole axis so that a motor of standard size mounted on said pads and a pump mounted in said hole are automatically alined with one another, the second end wall of the tower having a relief formed therein for accommodating passage of the motor shaft for mounting of a coupling in said tower connecting the motor shaft with the pump shaft, and a flat closure plate secured to and registering with the upper edge of the tower for mechanically shielding the coupling therein.

2. In an hydraulic power unit the combination comprising a horizontal bed plate of unitary cast construction and having a generally rectangular outline, an upstanding tower of hollow box shape cast integral with the bed plate and having first and second end walls together with side walls, a floor in said tower joining the walls and cast integral with the tower, means providing a motor mounting pad cast integral with the bed plate adjacent the second end wall, said first end wall having a flat surface formed thereon and a hole formed therein for flange mounting of an hydraulic pump, said motor pad being perpendicular to said flat surface and in a plane which is spaced at a predetermined distance with respect to the hole axis so that a motor of standard size mounted on said pad and a pump mounted in said hole are automatically alined with one another, the second end wall of the tower having a relief formed therein for accommodating passage of the motor shatft for mounting of a coupling in said tower connecting the motor shaft with the pump shaft.

3. In an hydraulic power unit the combination comprising a horizontal bed plate of unitary cast construction and having a generally rectangular outline, an upstanding hollow tower of hollow box shape cast integral with the bed plate and having first and second end walls together with side walls defining an upper edge lying in a generally horizontal plane, motor mounting pads cast integral with the bed plate adjacent the second end wall, said first end wall having a flat surface formed thereon and a hole formed therein for flange mounting an hydraulic pump, said motor pads being perpendicular to said flat surface and in a plane which is spaced at a predetermined distance wtih respect to the hole axis so that a motor of standard size mounted on said pads and a pump mounted in said hole are automatically alined with one another, the second end wall of the tower formed with a deep V notch to provide unobstructed access for the motor shaft when the motor is mounted on the mounting pads, and a closure plate secured to and registering with the upper edge of the tower for mechanically shielding the coupling therein.

4. In an hydraulic power unit the combination comprising a horizontal bed plate of unitary cast construction and having a generally rectangular outline, an upstanding tower of hollow box shape cast integral with the bed plate and having a first end wall together with side walls, means providing a motor mounting pad integrally cast with the bed plate adjacent the second end wall, said first end wall having a flat surface formed thereon and a hole formed therein for flange mounting of an hydraulic pump, said motor pad being perpendicular to said fiat surface so that a motor mounted on said pad and a pump mounted in said hole are alined with one another, the second end wall of the tower being open to accommodate passage of the motor shaft for mounting of a coupling in said tower connecting the motor shaft with the pump shaft, a reservoir of box shape, said bed plate having a continuous depending skirt cast integnal on its underside and spaced 6 inwardly from the peripheral edge of the plate for registered reception in an opening formed in the top of the reservoir, and means for releasably securing the bed plate to the reservoir.

5. For use with a hydraulic power unit having a motor and a hydraulic pump driven by said motor through a shaft coupling, a horizontal bed plate of unitary cast construction and having a generally rectangular outline, an upstanding tower of hollow box shape cast integral with the bed plate and having first and second end walls together with side walls defining an upper edge lying in a substantial horizontal plane, motor mounting pads integrally cast with the bed plate adjacent the second end wall, said first end wall having a hat surface formed thereon and a hole bored therein for flange mounting of the hydraulic pump, said motor pads being perpendicular to said flat surface and in a plane which is spaced at a predetermined distance with respect to the hole axis so that a motor of standard size mounted on said pads and a pump mounted on said flat surface with its shaft in said hole are alined with one another, the second end wall of the tower having a deep V notch to accommodate passage of the motor shaft for mounting of the coupling in said tower connecting the motor shaft with the pump shaft, an internal floor interconnecting the end and side walls of the tower, said floor being spaced above the surface of the plate and below the level of the V notch, a tflat closure plate secured to and registering with the upper edge of the tower for mechanically shielding the coupling therein, a reservoir of box shape, said bed plate having a continuous depending strip cast integrally on its under side and spaced inwardly from the peripheral edge of the plate for registered reception in an opening formed in the top of the reservoir, and means defining hold-down catches carried by the reservoir for releasably securing the bed plate to the reservoir.

References Cited by the Examiner UNITED STATES PATENTS 2,1695 14 8/ '39 Buzzard et al. 222-433 X 2,250, 306 7 41 La Bour. 3,042,266 7/ 62 Mics 222-433 X LOUIS J. DEMBO, Primary Examiner, HADD S. LANE, Examiner, 

1. IN AN HYDRAULIC POWER UNIT THE COMBINATION COMPRISING A HORIZONTAL BED PLATE OF UNITARY CAST CONSTRUCTION AND HAVING A GENERALLY RECTANGULAR OUTLINE, AN UPSTANDING TOWER OF HOLLOW OX SHAPE CAST INTEGRAL WITH THE BED PLATE AND HAVING FIRST AND SECOND END WALLS TOGETHER WITH SAID WALLS DEFINING AN UPPER EDGE LYING IN A SUBSTANTIALLY HORIZONTAL PLANE, MOTOR MOUNTING PADS INTEGRALLY CAST WITH THE BED PLATE ADJACENT THE SECOND END WALL, SAID FIRST END WALL HAVING A FLAT SURFACE FORMED THEEON AND A HOLE BORED THEREIN FOR FLANGE MOUNTING OF AN HYDRAULIC PUMP, SAID MOTOR PADS BEING PERPENDICULAR TO SAID FLAT SURFACE AND IN A PLANE WHICH IS SPACED AT A PREDETERMINED DISTANCE WITH RESPECT TO THE HOLE AXCIS SO THAT A MOTOR OF STANDARD SIZE MOUNTED ON SAID PADS AND A PUMP MOUNTED IN SAID HOLE ARE AUTOMATICALLY ALINED WITH ONE ANOTHER, THE SECOND END WALL OF THE TWOER HAVING A RELIEF FORMED THEREIN FOR ACCOMMODATING PASSAGE OF THE MOTOR SHAFT FOR MOUNTING OF A COUPLING IN SAID TOWER CONNECTING THE MOTOR SHAFT WITH THE PUMP SHAFT, AND A FLAT CLOSURE PLATE SECURED TO AND REGISTERING WEITH THE UPPER EDGE OF THE TOWER FOR MECHANICALLY SHIELDING THE COUPLING THEREIN. 